PubMed Health⌕ Search

Biomedical subjects

P Raggi

Publications and source records attributed to P Raggi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Electron beam tomography as an endpoint for clinical trials of antiatherosclerotic therapy.

Current antiatherosclerotic therapies are highly effective and have induced a factual reduction in morbidity and mortality related to atherosclerotic disease. This makes it difficult for clinical researchers to demonstrate a further reduction in hard events. On the other hand, angiographic studies have conclusively demonstrated that coronary artery disease regression can be used as a valid surrogate endpoint. In fact, small improvements in luminal diameter stenosis corresponded to a substantial reduction in event rates. However, because coronary angiography is invasive and expensive, other surrogate endpoints may be more desirable to ascertain the effectiveness of therapy. With electron beam tomography imaging the coronary artery tree is visualized noninvasively and vascular calcification, a marker of atherosclerotic disease, is easily detected and its extent quantified. Preliminary studies have shown that this technology provides an opportunity to serially monitor the effectiveness of medical therapy for coronary artery disease at low cost and low risk for the patient.

Animals↗
PubMed2000

Monitoring the effectiveness of preventive interventions using progression of coronary calcification with electron beam tomography.

Angiographic studies have demonstrated that progression of coronary artery disease can be slowed and in some cases regression obtained with appropriate medical therapies. However, coronary angiography is invasive and expensive. Detection of coronary artery calcification, a marker of atherosclerotic disease, with electron beam tomography imaging is achieved non-invasively and at a much lower cost. Therefore, this technology provides an opportunity to serially monitor the clinical effectiveness of medical therapy for coronary artery disease and could be useful for development of new therapies for atherosclerosis.

Calcinosis↗
PubMed2000

Is mitral valve prolapse due to cardiac entrapment in the chest Cavity? A CT view.

BACKGROUND: Mitral valve prolapse (MVP) is the most frequently diagnosed valvular disease, but its pathophysiology remains elusive. Its complete absence in 1,734 neonatal echocardiographic studies suggests that this may be an acquired rather than a congenital disease. We observed several patients with distorted cardiac and valvular anatomies on electron beam CT (EBCT) images of the chest who reported symptoms reminiscent of MVP. In these patients, the heart is compressed between the spine and the anterior chest wall and it appears trapped in a chest cavity that is too small for its size. METHODS: We performed EBCT in 66 patients with echocardiographically proven MVP and no clinical pectus excavatum (group A; 80% were women; mean age, 48 +/- 12 years) and in 96 control patients without MVP by echocardiography (group B; 72% were women; mean age, 49 +/- 10 years). EBCT alone was also performed on 200 patients who had reported atypical chest discomfort and palpitations to their physicians (group C) and on 200 asymptomatic patients (group D). The EBCT measurements included the following: anteroposterior chest diameter (APD); the angle formed by the confluence of the mitral valve ring with the interatrial septum (ANGLE); and the contact area between the posterior surface of the anterior chest wall and the myocardium (CA). Entrapment was considered present if the individual patient's measurements varied by more than two SDs compared to measurements made in control subjects (group B). RESULTS: EBCT images demonstrated cardiac entrapment in 82% of group A patients and in 4.2% of group B patients (p < 0.001). ANGLE and CA were significantly larger in MVP patients than in group B patients (114 +/- 9 degrees vs 91 +/- 5 degrees and 6,230 +/- 2,020 mm(2) vs 476 +/- 1,009 mm(2), respectively; p < 0.001 for both comparisons), while APD was significantly smaller (91 +/- 16 mm vs 128 +/- 17 mm, respectively; p < 0.001). The prevalence of entrapment was significantly greater in group C patients than in group D patients (22% vs 6.5%; p < 0. 001). CONCLUSIONS: MVP may be an acquired condition caused by a growth disproportion between the heart and the chest cavity, with distortion of the mitral valve annulus and subsequent leaflet prolapse. A narrow APD, a wide ANGLE, and a large CA characterize this condition. Similar findings are found in a sizable proportion of patients with atypical chest pain symptoms and palpitations.

Adult↗
PubMed2000

Sensitivity of two electron beam tomography protocols for the detection and quantification of coronary artery calcium.

OBJECTIVE: The purpose of this study was to compare the sensitivity of two electron beam tomography protocols for detection and quantification of coronary artery calcium. SUBJECTS AND METHODS: We selected 101 patients (57% men, mean age 53 +/- 10 years) to undergo two consecutive electron beam tomography and acquired imaging with both a 6-mm and a 3-mm slicing protocol. Three pixels (area, 1.03 mm(2)) and a minimal density of 130 H were used for definition of calcified plaque. RESULTS: We found coronary artery calcifications in 46 patients when we used a 6-mm protocol and in 61 patients when we used a 3-mm protocol (p < 0.001). The average total calcium score was 77 (+/-140) with a 6-mm protocol and 251 (+/-395) with a 3-mm protocol (p < 0.005). The average number of calcified lesions per patient was 1.7 for a 6-mm protocol and 3.7 for a 3-mm protocol (p < 0.01). Of 179 individual lesions seen using a 3-mm protocol, 103 (58%) were missed using a 6-mm protocol, and only 27% of the lesions with a calcium score less than or equal to 40 seen with a 3-mm protocol were detected with 6-mm slicing (p < 0.001). The mean lesion attenuation with a 6-mm protocol was 160 (+/-42) H, compared with 218 (+/-44) H with a 3-mm protocol (p < 0.001), indicating a significantly greater partial volume averaging with the former protocol. CONCLUSION: A 6-mm slicing protocol is significantly less sensitive than a 3-mm protocol for the detection and quantification of coronary artery calcium. Since one third of coronary events occur in patients with low calcium scores, a 6-mm protocol might be unreliable for risk assessment because of substantial loss of information in this calcium score range.

Calcinosis↗
PubMed2000

Detection and quantification of cardiovascular calcifications with electron beam tomography to estimate risk in hemodialysis patients.

Cardiovascular disease is the leading cause of death in dialysis patients, accounting for nearly half of all deaths among end-stage renal disease (ESRD) patients. Even young dialysis patients are at risk. Cardiovascular disease in chronic renal failure patients has been associated with elevated serum phosphorus levels and elevated calcium-phosphorus (Ca x P) product, and mismanagement of calcium and phosphorus metabolism has been implicated as a major factor in the development of soft tissue calcification and cardiovascular disease. ESRD patients frequently face hyperphosphatemia as well as excess calcium load, which elevate the Ca x P product, thereby contributing to the development of calcific complications. Electron beam computed tomography (EBCT) can be used to detect different calcification stages in a variety of tissues, and is a sensitive tool for detecting calcified coronary artery plaques as well as cardiac and valvular calcifications. Hemodialysis patients have high calcium scores on EBCT imaging, and these are associated with elevations in Ca x P product. In a recent study, patients with calcification were found to have had twice the daily calcium intake from calcium-based phosphate binders than patients without calcification. Strategies to reduce cardiac risk in hemodialysis patients include use of a dialysate low in calcium, use of vitamin D analogs that are less calcemic, and use of calcium-free phosphate binders. EBCT can be a useful adjunct to these therapies, since it permits sensitive and quantitative initial assessment, as well as ongoing monitoring of disease progression.

Calcinosis↗
PubMed1998

Effect of HMG-CoA reductase inhibitors on coronary artery disease as assessed by electron-beam computed tomography.

BACKGROUND: Angiographic studies of the regression of coronary artery disease are invasive and costly, and they permit only limited assessment of changes in the extent of atherosclerotic disease. Electron-beam computed tomography (CT) is noninvasive and inexpensive. The entire coronary-artery tree can be studied during a single imaging session, and the volume of coronary calcification as quantified with this technique correlates closely with the total burden of atherosclerotic plaque. METHODS: We conducted a retrospective study of 149 patients (61 percent men and 39 percent women; age range, 32 to 75 years) with no history of coronary artery disease who were referred by their primary care physicians for screening electron-beam CT. All patients underwent base-line scanning and follow-up assessment after a minimum of 12 months (range, 12 to 15), and a volumetric calcium score was calculated as an estimate of the total burden of plaque. Treatment with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors was begun at the discretion of the referring physician. Serial measurements of low-density lipoprotein (LDL) cholesterol were obtained, and the change in the calcium-volume score was correlated with average LDL cholesterol levels. RESULTS: One hundred five patients (70 percent) received treatment with HMG-CoA reductase inhibitors, and 44 patients (30 percent) did not. At follow-up, a net reduction in the calcium-volume score was observed only in the 65 treated patients whose final LDL cholesterol levels were less than 120 mg per deciliter (3.10 mmol per liter) (mean [+/-SD] change in the score, -7+/-23 percent; P=0.01). Untreated patients had an average LDL cholesterol level of at least 120 mg per deciliter and at the time of follow-up had a significant net increase in mean calcium-volume score (mean change, +52+/-36 percent; P<0.001). The 40 treated patients who had average LDL cholesterol levels of at least 120 mg per deciliter had a measurable increase in mean calcium-volume score (25+/-22 percent, P<0.001), although it was smaller than the increase in the untreated patients. CONCLUSIONS: The extent to which the volume of atherosclerotic plaque decreased, stabilized, or increased was directly related to treatment with HMG-CoA reductase inhibitors and the resulting serum LDL cholesterol levels. These changes can be determined noninvasively by electron-beam CT and quantified with use of a calcium-volume score.

Adult↗
PubMed1998

Detection of coronary vasospasm by posthyperventilation technetium-99m sestamibi single-photon emission computed tomography imaging in patients with coronary artery disease.

Forced hyperventilation is simple, safe to perform, and can be used as a provocative test for coronary vasospasm. This study assesses whether a vasospastic component of angina might be detected in patients with angiographically "nonobstructive" coronary artery disease by posthyperventilation technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) cardiac imaging. Eleven patients with angiographically nonobstructive coronary artery disease underwent Tc-99m sestamibi SPECT imaging at rest and after forced hyperventilation. Vessel diameters were measured by quantitative angiography before and after forced hyperventilation, and posthyperventilation SPECT images were compared with dipyridamole Tc-99m sestamibi stress images. Forced hyperventilation resulted in a 15% reduction in coronary artery diameter in stenotic segments (p <0.01), and a 17% reduction in adjacent nonstenotic segments (p <0.001). Myocardial uptake of Tc-99m sestamibi in segments perfused by vessels with angiographically nonobstructive stenoses was reduced by 24% following forced hyperventilation (p <0.001) compared with only 4% following dipyridamole (p <0.02). These findings suggest that posthyperventilation Tc-99m sestamibi SPECT imaging in patients with angina pectoris and nonobstructive coronary artery disease may be useful in identifying a vasospastic component of angina.

Angina Pectoris↗
PubMed1998

Comparison of technetium-99m tetrofosmin and thallium-201 single-photon emission computed tomographic imaging for detection of myocardial perfusion defects in patients with coronary artery disease.

OBJECTIVES: We compared dipyridamole technetium-99m (Tc-99m) tetrofosmin and thallium-201 (Tl-201) single-photon emission computed tomographic (SPECT) imaging with respect to the detection rate of perfusion abnormalities in 26 patients with angiographic coronary artery disease (CAD). BACKGROUND: Experimental studies have shown that myocardial extraction of Tc-99m tetrofosmin is lower than that of Tl-201 at high flow rates, resulting in less severe defects with vasodilator stress. It is uncertain whether this results in a lower sensitivity than Tl-201 for detecting coronary stenoses with vasodilator stress in patients. METHODS: Twenty-six patients with CAD underwent both dipyridamole Tl-201 and Tc-99m tetrofosmin SPECT. Tomographic images were scored for initial defects and the presence of reversibility. Defect magnitude was computer quantitated. RESULTS: Of the 26 patients, 25 had defects on both Tl-201 and Tc-99m tetrofosmin SPECT images. Of 340 segments analyzed, 102 had defects by Tl-201 and 92 by Tc-99m tetrofosmin (p = NS). Whereas Tl-201 detected 27 fixed defects in 12 patients, Tc-99m tetrofosmin identified 37 fixed defects in 14 patients (p = NS). In contrast, Tl-201 identified more reversible and partially reversible defects than did Tc-99m tetrofosmin (89 vs. 55, p = 0.002). The average defect magnitude (percent normal) was similar for defects concordantly graded as fixed (38 +/- 3.0% for Tl-201 vs. 42 +/- 4% [mean +/- SEM] for Tc-99m tetrofosmin, p = NS). The average defect magnitude for defects concordantly graded as completely reversible was significantly more severe on Tl-201 than on Tc-99m tetrofosmin (49 +/- 3% vs. 58 +/- 3%) SPECT images. A significantly greater defect magnitude for Tl-201 was also found for defects concordantly classified as partly reversible (30 +/- 4% for Tl-201 vs. 45 +/- 5% for Tc-99m tetrofosmin). CONCLUSIONS: With dipyridamole stress, 1) at least one defect was seen on both Tl-201 and Tc-99m tetrofosmin SPECT images; 2) Tc-99m tetrofosmin SPECT identified fewer reversible defects than did Tl-201, but showed a similar number of fixed defects; 3) the magnitude of reversible defects seen on Tc-99m tetrofosmin images was less, whereas fixed defects were similar for both tracers; 4) reversible defects seen on Tl-201 and not on Tc-99m tetrofosmin SPECT images were predominantly regions perfused by mild coronary stenoses.

Adult↗
PubMed1998

Coronary artery disease: improved reproducibility of calcium scoring with an electron-beam CT volumetric method.

PURPOSE: To assess the variability and reproducibility of a volumetric calcium score calculated with electron-bean computed tomographic (CT) scans of coronary arteries. MATERIALS AND METHODS: Two sets of electron-beam CT scans were obtained in patients with coronary calcification (group A) or known risk factors for coronary arterial disease (group B). The second set or scans was obtained after a brief interval (group A, n = 52) or after 1 year with no risk modification (group B, n = 27). Traditional (plaque area and attenuation) and volumetric calcium scores were calculated for each patient and lesion. RESULTS: The median percentage change for individual lesions in group A was 13% for the volumetric and 19% for the traditional score. The overall reduction in error with the volumetric score was 40% (P < .001). The median percentage change for group A patient totals was 9% for the volumetric and 15% for the traditional score (P < .001). In group B patients, the median volumetric score increased by 44% after 1 year. CONCLUSION: The volumetric score showed better reproducibility than the traditional score, and its variability was considerably less than the score increase in untreated patients after 1 year. The reproducibility of the volumetric method makes it useful for assessing the progression of coronary arterial disease on serial electron-beam CT studies.

Calcinosis↗
PubMed1998

Influence of prior ACE inhibitor therapy on morbidity and mortality following acute myocardial infarction.

BACKGROUND: Angiotensin-converting enzyme inhibitor (ACE-I) therapy reduces complications of acute myocardial infarction (MI) even when the therapy is started very early after an acute event. This study sought to determine whether administration of ACE-I therapy prior to acute MI is related to subsequent patient morbidity and mortality. METHODS: Chart review of 318 consecutive patients admitted between September 1995 and December 1996 with a diagnosis of acute MI. Outcome data were compared between patient groups receiving ACE-I therapy prior to infarction and those who were not. RESULTS: Sixty-four patients (20%) were receiving prior ACE-I therapy. They experienced smaller MIs, as determined by peak creatine kinase elevation (1066 +/- 134 vs. 1510 +/- 95 IU; p < 0.05), and fewer Q-wave infarctions (p < 0.05) than did patients who were not receiving prior treatment. The severity of coronary artery disease, defined by an angiographic score, was similar for the two groups. Mortality rates, including patients resuscitated from ventricular fibrillation, were similar within the first 72 hours of admission (3% vs. 2%; p = NS), but patients receiving prior ACE-I therapy showed a greater long-term in-hospital mortality rate (14% vs. 5%; p < 0.05) related to more heart failure deaths. Multivariate logistic regression analysis identified age, treatment with digoxin prior to acute MI, and left ventricular ejection fraction after infarction, but not ACE-I therapy taken prior to infarction, as significant independent predictors of mortality and combined morbidity and mortality. CONCLUSIONS: In a group of patients experiencing an acute MI, those receiving prior ACE-I therapy were more likely to sustain fewer transmural MIs and smaller infarcts. Chronic ACE-I therapy may have cardioprotective effects during acute myocardial ischemia.

Acute Disease↗
PubMed1998

Prevalence of patent foramen ovale and its contribution to hypoxemia in patients with obstructive sleep apnea.

STUDY OBJECTIVES: The objectives of this study were (1) to assess the prevalence of patent foramen ovale (PFO) by means of contrast transesophageal echocardiography (TEE) in patients with obstructive sleep apnea, and (2) to determine the potential contribution of right to left interatrial shunting to systemic oxygen desaturation following the performance of Valsalva maneuver. DESIGN: Performance of contrast TEE during Valsalva maneuver with simultaneous measurement of systemic arterial oxygen saturation (SaO2) by means of pulse oximetry in patients with obstructive sleep apnea and a control group. SETTING: Government teaching hospital, university hospital affiliate. PATIENTS: Study group comprised 48 patients with documented obstructive sleep apnea and 24 control subjects. INTERVENTIONS: Sleep studies, contrast TEE, Valsalva maneuver, pulse oximetry. MEASUREMENTS AND RESULTS: Thirty-three of 48 patients with obstructive sleep apnea compared with 4 of 24 control patients had a detectable PFO (69% vs 17%; p < 0.0001). All sleep apnea patients had comparable baseline SaO2 regardless of the presence of a PFO (93.9+/-1.7% vs 95+/-1.2%; p=not significant). After performance of a Valsalva maneuver, however, a significantly greater fall in SaO2 was observed in patients with obstructive sleep apnea and PFO compared with patients with obstructive sleep apnea without PFO (-2.4 +/- 1.5% vs -1.3 +/- 0.6%; p=0.007). A statistically significant fall in SaO2 (defined as > 4 SD of recorded SaO2 values after Valsalva maneuver in patients without PFO) was found in one third of patients with sleep apnea and PFO. CONCLUSION: We conclude that there is an increased prevalence of PFO in patients with obstructive sleep apnea that could contribute to significant hypoxemia after a Valsalva maneuver in approximately one third of these patients.

Aged↗
PubMed1996

Uncommon etiologies of atrial fibrillation.

A newly diagnosed atrial fibrillation warrants a full investigation of the etiopathogenesis of this common arrhythmia. In the adult population, the most frequently associated conditions are systemic hypertension, coronary artery disease, mitral valvulopathy, congestive heart failure, and hyperthyroidism. Nevertheless, more infrequent and even rare, yet correctable, etiologies should not be overlooked. We describe three patients who presented to our hospital with a first episode of atrial fibrillation and who subsequently were demonstrated to have very unusual cardiovascular pathologies subtending this common arrhythmia. In all three cases, trans-esophageal echocardiography was instrumental in reaching an accurate diagnosis that was later confirmed at surgery.

Adult↗
PubMed1996

MRI misinterpretation of spontaneous echo-contrast as a large left atrial thrombus.

A magnetic resonance imaging of the heart was obtained in a patient with history of mitral valve replacement, in whom cor triatriatum dexter was suspected. Dense left atrial echo-contrast, visualized during a previous transesophageal echocardiography, was incorrectly interpreted as a large thrombus extending into the pulmonary veins and the patient was referred for cardiac surgical evaluation.

Aged↗
PubMed1995

Doppler echocardiographic methods to estimate severity of aortic stenosis.

The continuity equation should be regarded as the Doppler echocardiographic gold standard for estimation of valve area in patients with aortic stenosis, but a quick, easy, and inexpensive screening test may be desirable in an era of medical cost containment. Aortic valve leaflet separation could be used as such a test. In fact, it could prove especially useful in cases where calculations using the continuity equation or the fractional shortening-velocity ratio are problematic.

Aged↗
PubMed1995

Transient severe myocardial ischemia during septic shock in a young woman with AIDS.

A 29-year-old woman with acquired immunodeficiency syndrome (AIDS) was admitted to the intensive care unit with a diagnosis of septic shock. During intensive hemodynamic support with intravenous dopamine, she developed electrocardiographic ischemic changes compatible with an acute injury pattern. The pattern disappeared readily and was not followed by any subsequent enzymatic evidence of myocardial necrosis. Intensive hemodynamic support with intravenous catecholamines may induce myocardial ischemia even in young AIDS patients with no apparent risk for coronary artery disease.

Acquired Immunodeficiency Syndrome↗